Isocyanate reactive mixture and the use thereof in the manufacture of flexible polyurethane foams

ABSTRACT

The present invention is directed to a reactive mixture for use in preparing a flexible polyurethane foam and to the foams produced therefrom. The reactive mixture broadly comprises 
     (A) from more than 0 up to 3 parts by weight per 100 parts by weight of components (B) and (C) of an amine of the formula: 
     
         H.sub.2 N--R--NH.sub.2 
    
      where R is a C 4  to C 10  straight or branched alkylene group, or a C 4  to C 15  alicyclic group, 
     (B) from 0 to 30% by weight of a polyoxyalkylene polyamine having a molecular weight of from about 400 to about 5000 and containing from 2 to 3 primary amino groups, and 
     (C) from 700 to 100% by weight of one or more polyether polyhydroxyl compounds having hydroxyl functionalities from about 2 to 3 and molecular weights of from about 1000 to about 10,000, the percents of components (B) and (C) totalling 100%.

BACKGROUND OF THE INVENTION

It is known in the art to manufacture flexible polyurethane foams usingmixtures of methylene bis(phenyl isocyanate) ("MDI") and polymethylenepoly(phenyl isocyanate) ("polymeric MDI") and prepolymers based on suchmixtures. See, e.g., U.S. Pat. Nos. 4,239,856, 4,256,849, 4,261,852, and4,365,025. Typical isocyanate reactive materials suggested for use withsuch isocyanates include (i) mixtures of polyether triols havingmolecular weights of from 2000 to 7000 with diethanolamine (U.S. Pat.No. 4,239,856); (ii) mixtures of 400 to 10,000 molecular weightpolyethers having primary hydroxyl groups with low molecular weightactive hydrogen containing materials (U.S. Pat. No. 4,256,849); (iii)polyoxypropylene or poly(oxypropylene-oxyethylene) diols or triolshaving equivalent weights of from 700 to 2000 (U.S. Pat. No. 4,261,852)and (iv) water (U.S. Pat. No. 4,365,025).

It is also known to use various low molecular weight crosslinkers in themanufacture of flexible foams. U.S. Pat. No. 3,067,148 describes the useof tetrahydric compounds derived from ethylene diamine and alkyleneoxides. U.S. Pat. No. 3,948,825 describes the use of reaction productsof methylene dianiline and alkylene oxides. U.S. Pat. No. 4,569,952describes the use of an addition product of an alkylene oxide and anaromatic diamine and a mixture of the addition product with analkanolamine.

Finally, Dupont has recently introduced an amine sold as Dytek amine fora variety of uses. The Dytek amine is described as2-methylpentamethylenediamine. Among the uses suggested in productbulletin entitled "Amines" is the use as a chain extender forpolyurethanes.

While many foam formulations based on MDI and polymeric MDI giveadequate properties for many applications, it is generally difficult tohave good processability over a broad isocyanate index range.Additionally, it would be desirable to develop a foam having high tearstrength, high elongation, and low compression set for automotiveseating and headrests and for nonautomotive seating.

DESCRIPTION OF THE INVENTION

The present invention is directed to a reactive mixture for use inproducing flexible polyurethane foams. The reactive mixture gives goodprocessability over a broad isocyanate index range. Foams of a widerange of densities can be produced with good mold vent stability over awide isocyanate index range. The flow times of the foam systems areextended, which, when combined with the improved vent stability, givesmuch improved molded parts. The foams produced from the reactionmixtures have improved green strength upon demold with reduced, and, inmost cases, eliminated finger printing. In addition, the use ofcell-openers is not required. Finally, when using the preferredformulations, the foams produced have high tear strengths, highelongations, and low compression sets.

More particularly, the isocyanate reactive mixtures of the presentinvention comprise:

(A) from more than 0 up to 3 parts by weight per 100 parts by weight ofcomponents (B) and (C) of an amine of the formula:

    H.sub.2 N--R--NH.sub.2

where R is a C₃ to C₁₀ straight or branched alkylene group or a C₄ toC₁₅ alicyclic group.

(B) from 0 to 30% by weight of a polyoxyalkylene polyamine having amolecular weight of from about 400 to about 5000 and containing from 2to 3 primary amino groups, and

(C) from 70 to 100% by weight of one or more polyether polyhydroxylcompounds having hydroxyl functionalities of from 2 to 3 and molecularweights of from about 1000 to about 10,000, the percents by weight ofcomponent (B) and component (C) totalling 100%.

Component (A) is preferably used in an amount of from 0.05 to 2.5 partsby weight and most preferably in an amount of from 0.25 to 1.5 parts byweight. Component (B) is preferably used in an amount of from 1 to 20%by weight and most preferably from 2.5 to 15% by weight, with component(C) preferably used in an amount of from 80 to 99% by weight and mostpreferably from 85 to 97.5% by weight. The preferred and most preferredranges produce foams of the best overall physical properties. The foamsof the present invention are prepared by reacting the above reactionmixture with a polymethylene poly(phenyl isocyanate) containing fromabout 40 to about 85% by weight of methylene bis(phenyl isocyanate) or aprepolymer of such isocyanate, with such prepolymer having an isocyanatecontent of from about 15 to about 30% by weight. The isocyanates usefulherein are generally known and are produced by reacting phosgene withaniline/formaldehyde condensates. Known processes for preparing theaniline/formaldehyde condensates and the resultant polyisocyanates aredescribed in the literature and in many patents, for example, U.S. Pat.Nos. 2,683,730, 2,950,263, 3,012,008, 3,344,162 and 3,362,979.Additionally useful isocyanates are described in U.S. Pat. No.4,256,849, the disclosure of which is herein incorporated by reference.Useful prepolymers are described in U.S. Pat. No. 4,261,852, thedisclosure of which is herein incorporated by reference. In general theisocyanate index is from 60 to 140, and is preferably from 90 to 120.

Component (A) of the reaction mixture of the present invention is anamine of the formula:

    H.sub.2 N--R--NH.sub.2

where R is a C₃ to C₁₀ straight or branched chain alkylene group or a C₄to C₁₅ alicyclic group. Useful diamines include the various straight andbranched chain isomers of diaminopropane, diaminobutane, diaminopentane,diaminohexane, diaminoheptane, diaminooctane, diaminononane, anddiaminodecane. Specific useful diamines include 1,2- and1,3-diaminopropane; 1,3-,2,3-, and 1,4-diaminobutane;1,2-diamino-2-methylpropane; 1,5-diaminopentane;1,4-diamino-1-methylbutane; 1,4-diamino-2-methylbutane;1,3-diamino-1-ethylpropane; 1,3-diamino-1,1-dimethylpropane;1,3-diamino-1,2-dimethylpropane; 1,3-diamino-2,2-dimethylpropane;1,5-diamino-2-methylpentane; 1,6-diaminohexane and the like. Usefulalicyclic diamines include the various isomers of diaminocyclobutane,diaminocyclopentane, diaminocyclohexane, diaminocycloheptane,diaminocyclooctane, and diaminocyclononane. Also useful are thediamino-1-methylcyclohexanes; the methylenebis(cyclohexylamines); thediamino-1-methylcyclopentanes; the diaminodimethylcyclohexanes;isophorone diamine; and the like. It is presently preferred to use thosediamines where R is a branched chain alkylene group. The most preferredmaterial is 1,5-diamino-2-methylpentane.

Component (B) of the reaction mixture is a polyoxyalkylene polyaminehaving a molecular weight of from about 400 to about 5000, and havingfrom 2 to 3 primary amine groups. Such polyamines are known in the art.One method for preparing such amines is the amination of polyhydroxypolyethers (e.g.,polypropylene glycols) by a reaction with ammonia inthe presence of Raney nickel and hydrogen (Belgian Patent No. 634,741).U.S. Pat. No. 3,654,370 discloses the preparation of polyoxyalkylenepolyamines by reaction of the corresponding polyol with ammonia andhydrogen in the presence of a nickel, copper, or chromium catalyst. Thepreparation of polyethers containing amino end groups by thehydrogenation of cyanoethylated polyoxypropylene ethers is described inGerman Patent No. 1,193,671. Other methods for the preparation ofpolyoxyalkylene polyamines are described in U.S. Pat. Nos. 3,155,728 and3,236,895 and French Patent No. 1,551,605. Commercially availablepolyether polyamines are sold by Texaco under the Jeffamine tradename.

Component (C) comprises one or more polyether polyhydroxyl compoundshaving hydroxyl functionalities of from 2 to 3, and having molecularweights of from about 1000 to about 10,000, and preferably from about2000 to about 6000. Such polyethers are generally known in the art.These polyethers may be obtained by polymerizing epoxides, such asethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran,styrene oxide or epichlorohydrin in the presence of Lewis catalysts suchas BF₃. Polymerization may also be accomplished by the addition ofepoxides (preferably ethylene and/or propylene oxide) either inadmixture or successively, to compounds containing reactive hydrogenatoms such as water or alcohols. Examples of suitable reactive compoundsinclude ethylene glycol, 1,3- and 1,2-propylene glycol, trimethylolpropane, glycerol and the like. Also useful are the polyetherscontaining high molecular weight polyadducts and polycondensates orpolymers in finely dispersed or dissolved form. Such polyethers may beobtained by polyaddition reactions (for example, reactions betweenpolyisocyanates and aminofunctional compounds) and polycondensationreactions (for example, between formaldehyde and phenols and/or amines)in situ in the above described polyethers. Such processes are describedin German Auslegeschriften No. 1,168,075 and 1,260,142 and in GermanOffenlegungsschriften Nos. 2,324,134, 2,423,984, 2,512,385, 2,513,815,2,550,796, 2,550,797, 2,550,833, 2,550,862, 2,633,293, and 2,639,254.See also U.S. Pat. Nos. 3,325,421, 4,042,537, 4,089,835, 4,293,470,4,296,213, and 4,374,209. Also useful are the so-called polymer polyolsobtained by polymerizing one or more ethylenically unsaturated monomersin a polyether. Such polymer polyols are described in U.S. Pat. Nos.3,383,351, 3,304,273, 3,523,093, 3,110,685 and RE 28,715 and 29,118.Polymer polyols are commercially available from Bayer AG, BASF, andUnion Carbide. Regardless of the specific polyether used herein, it isgenerally preferred to use polyethers containing primary hydroxylgroups.

According to the invention, water and/or readily volatile organicsubstances are used as blowing agents. Suitable organic blowing agentsinclude, for example, acetone, ethyl acetate and halogen substitutedalkanes such as methylene chloride, chloroform, ethylidene chloride,vinylidene chloride, monofluorotrichloromethane, chlorodifluoromethaneas well as butane, hexane, heptane and diethyl ether. The effect of ablowing agent can also be obtained by the addition of compounds whichdecompose at temperatures above room temperature to release gases suchas nitrogen, e.g., azo compounds such as azoisobutyric acid nitrile.Further examples of blowing agents and the use of blowing agents areknown and have been described, e.g., in Kunststoff-Handbuch, Volume VII,published by Vieweg and Hochtlen, Carl-Hanser-Verlag, Munich 1966, e.g.,on pages 108 and 109, 432 to 455 and 507 to 510.

Catalysts are also frequently used according to the invention. Thecatalysts added are generally known and include tertiary amines such astriethylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine,N-cocomorpholine, N,N,N',N"-tetramethyl-ethylenediamine,1,4-diaza-bicyclo-(2,2,2)-octane,N-methyl-N'-dimethyl-aminoethylpiperazine, N,N-dimethylbenzylamine,bis-(N,N-diethyl-aminoethyl)-adipate, N,N-diethylbenzylamine,pentamethyl-diethylenetriamine, N,N-dimethylcyclohexylamine,N,N,N',N'-tetramethyl-1,3-butanediamine,N,N-dimethyl-B-phenylethylamine, 1,2-dimethylimidazole,2-methylimidazole and the like. Also useful are the commerciallyavailable tertiary amines such as Niax A1 and Niax A107, available fromUnion Carbide; Thancat DD, available from Texaco; and the like. Mannichbases known per se obtained from secondary amines such as dimethylamineand aldehydes, preferably formaldehyde, or ketones such as acetone,methyl ethyl ketone or cyclohexanone and phenols such as phenolnonylphenol or bisphenol may also be used as catalysts. Examples ofcatalyst which consist of tertiary amines having hydrogen atoms whichare reactive with isocyanate groups include triethanolamine,triisopropanolamine, N-methyl-diethanolamine, N-ethyl-diethanolamine,N,N-dimethyl-ethanolamine and their reaction products with alkyleneoxides such as propylene oxide and/or ethylene oxide.

Silaamines having carbon-silicon bonds as described, e.g., in GermanPatent No. 1,229,290 and U.S. Pat. No. 3,620,984 may also be used ascatalysts. Examples include 2,2,4-trimethyl-2-silamorpholine and1,3-diethylaminoethyltetramethyldisoloxane.

Basic nitrogen compounds such as tetraalkylammonium hydroxides, alkalimetal hydroxides such as sodium phenolate and alkali metal alcoholatessuch as sodium methylate may also be used as catalysts.Hexahydrotriazines are also suitable catalysts.

Organic metal compounds may also be used as catalysts according to theinvention, in particular organic tin compounds. The organic tincompounds used are preferably tin(II) salts of carboxylic acids such astin(II) acetate, tin(II) octoate, tin(II) ethyl hexoate and tin(II)laurate and tin(IV) compounds such as dibutyl tin oxide, dibutyl tindichloride, dibutyl tin diacetate, dibutyl tin dilaurate, dibutyl tinmaleate or dioctyl tin diacetate. All the above-mentioned catalysts may,of course, be used as mixtures.

Further examples of catalyst which may be used according to theinvention and details concerning the activity of the catalysts are knownand are described, e.g., in Kunststoff-Handbuch, Volume VII, publishedby Vieweg and Hochtlen, Carl-Hanser-Verlag, Munich 1966, pages 96 to102.

The catalysts, when used, are generally used in a quantity of betweenabout 0.001 and 10%, by weight, based on the quantity of primaryhydroxyl group containing polyethers.

Surface active additives such as emulsifiers and foam stabilizers mayalso be used according to the invention. Suitable emulsifiers include,e.g., the sodium salts of ricinoleic sulphonates or salts of fatty acidswith amines such as oleic acid diethylamine or stearic aciddiethanolamine. Alkali metal or ammonium salts of sulphonic acids suchas dodecylbenzene sulphonic acid or dinaphthylmethane disulphinic acidor of fatty acids such as ricinoleic acid or of polymeric fatty acidsmay also be used as surface active additives.

Polyether siloxanes are particularly suitable foam stabilizers,especially useful are those which are water soluble. These compoundsgenerally have a polydimethyl siloxane group attached to a copolymer ofethylene oxide and propylene oxide. Foam stabilizers of this kind areknown and have been described, for example, in U.S. Pat. Nos. 2,834,748,2,917,480 and 3,629,308. It may, however, be advantageous to carry outthe process according to the invention without foam stabilizers.

Other additives which may also be used according to the inventioninclude reaction retarders, e.g., substances which are acid in reactionsuch as hydrochloric acid or organic acid halides, cell regulators suchas paraffins or fatty alcohols or dimethyl polysiloxanes, pigments,dyes, flame retarding agents such as tris-chloroethyl phosphate,tricresyl phosphate or ammonium phosphate and polyphosphates,stabilizers against ageing and weathering, plasticizers, fungistatic andbacteriostatic substances, and fillers such as barium sulphate,kieselguhr, carbon black or whiting.

Other examples of surface active additives, foam stabilizers, cellregulators, reaction retarders, stabilizers, flame retarding substances,plasticizers, dyes, fillers and fungistatic and bacteriostaticsubstances which may be used according to the invention and detailsconcerning the use and mode of these additives are known and may befound, e.g., in Kunststoff-Handbuch, Volume VII, published by Vieweg andHochtlen, Carl-Hanser-Verlag, Munich 1966, on pages 103 to 113.

According to the invention, the components may be reacted together byknown processes often using mechanical devices such as those describedin U.S. Pat. No. 2,764,565. Details concerning processing apparatuswhich may be used according to the invention may be found inKunststoff-Handbuch, Volume VII, published by Vieweg and Hochtlen,Carl-Hanser-Verlag, Munich, 1966, pages 121 and 205.

According to the invention, the foaming reaction for producing foamproducts is often carried out inside molds. In this process, thefoamable reaction mixture is introduced into a mold which may be made ofa metal such as aluminum or a plastics material such as an epoxideresin. The reaction mixture foams up inside the mold to produce theshaped product. The process of foaming in molds is carried out toproduce a product having a cellular structure on its surface. Accordingto the invention, the desired result can be obtained by introducing justsufficient foamable reaction mixture to fill the mold with foam afterthe reaction is completed.

So-called external mold release agents known in the art, such assilicone waxes and oils, are frequently used when foaming is carried outinside the molds. The process may also be carried out with the aid ofso-called internal mold release agents, if desired, in combination withexternal mold release agents, e.g., described in GermanOffenlegungsschriften Nos. 2,121,670 and 2,307,589.

Cold setting foams may also be produced, as described in British PatentNo. 1,162,517 and German Offenlegungsschrift No. 2,153,086.

Foams may, of course, also be produced by the process of block foamingor by the laminator process known in the art. The products obtainableaccording to the invention may be used, for example, as upholstery orpadding materials.

The invention is further illustrated but is not intended to be limitedby the following examples in which all parts and percentages are byweight unless otherwise specified.

EXAMPLES

In the examples which follow, the following materials were used:

(A) POLYOL A: a glycerin initiated-propylene oxide/ethylene oxidepolyether (weight ratio of PO to EO of about 5:1) having a molecularweight of about 6000.

(B) POLYOL B: a propylene glycol initiated-propylene oxide/ethyleneoxide polyether (weight ratio of PO to EO of about 7:1) having amolecular weight of about 4000.

(C) POLYAMINE A: an approximately 400 molecular weight difunctionalprimary amine terminated polyether, available from Texaco as JeffamineD-400.

(D) POLYAMINE B: Jeffamine D2000, a 2000 molecular weight polypropyleneoxide diamine, available from Texaco.

(E) DYTEK A: 2-methylpentamethylenediamine, available from Dupont.

(F) SILOXANE A: B8002, a siloxane available from Goldschmidt.

(G) SILOXANE B: KS 43, a low molecular weight polyoxyalkylenepolysiloxane available from Bayer AG.

(H) CELL OPENER A: a glycerin based ethylene oxide/propylene oxidepolyether having an OH number of about 35.

(I) CELL OPENER B: a sorbitol initiated-propylene oxide/ethylene oxidepolyether (weight ratio of PO to EO of about 5:1) having an OH number of100.

(J) WATER

(K) ISOCYANATE: Mondur MRS-2, available from Mobay, apolymethylenepoly(phenyl isocyanate) containing 78% by weightdiisocyanate, having an isocyanate content of about 33%, an equivalentweight of about 127, and a viscosity of about 22 cps at 25° C.

In the examples, the components of the B-side were accurately weighedinto a suitable container and mixed using an air driven two blade mixer.The resultant mixture was then taken to the metering equipment. Themetering equipment was flushed with the mixture and calibrated for thedesired foam index.

The mixture was mixed with the isocyanate using high pressure meteringequipment (HENNECKE HK100) and a Hennecke MQ-12-2 self-cleaning mixhead.Process settings were as follows:

    ______________________________________                                        TEMPERATURE MIX/ISO:                                                                              80/80° F.                                          MIX PRESSURES MIX/ISO                                                                             2500/1600 psi                                             MOLD TEMP °F.                                                                              130-150                                                   MOLD RELEASE        Brulin 2023                                               DEMOLD TIME         3-5 minutes                                               ______________________________________                                    

The reaction mixture was metered into a 15 inch×15 inch×4 mold (whichhad been previously sprayed with the mold release), in an amountsufficient to give the desired foam density. The mold was then closedand the foam part demolded after the reaction was complete. The partswere labelled and tested for physical properties. The parts were agedunder standard ASTM conditions (50% RH, 72°-74°F.) for three days. Theparts were then tested under ASTM 2406 laboratories procedures asspecified in Chrysler MS-DC634.

The formulations used and the results obtained were as reported in thefollowing table (all amounts are in parts by weight):

                                      TABLE                                       __________________________________________________________________________    EXAMPLE  1  2  3  4  5  6  7  8  9  10 11 12 13 14 15 16  17                                                                              18                __________________________________________________________________________    B-SIDE:                                                                       POLYOL A 50 50 50 50 50 50 50 50 30 30 30 30 45 40 30 30 30 32                POLYOL B 50 50 50 50 50 50 50 50 60 60 60 60 52.5                                                                             55 60 60 60 66                POLYAMINE A                                                                            0.5                                                                              0.5                                                                              0.5                                                                              0.5                                                                              -- -- -- -- -- -- -- -- -- -- -- -- -- --                POLYAMINE B                                                                            -- -- -- -- -- -- -- -- 10 10 10 10 2.5                                                                              5  10 10 10 2                 CELL OPENER                                                                            4.0                                                                              4.0                                                                              4.0                                                                              4.0                                                                              -- -- -- -- -- -- -- -- -- -- -- -- -- --                CELL OPENER                                                                            -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 1  -- --                B                                                                             DYTEK A  -- -- -- -- 0.5                                                                              0.5                                                                              0.5                                                                              0.5                                                                              1  1  1  1  .5 .5 .5 .5 1  .2                SILOXANE A                                                                             0.25                                                                             0.25                                                                             0.25                                                                             0.25                                                                             -- -- -- -- -- -- -- -- -- -- -- -- -- --                SILOXANE B                                                                             -- -- -- -- 0.5                                                                              0.5                                                                              0.5                                                                              0.5                                                                              0.5                                                                              0.5                                                                              0.5                                                                              0.5                                                                              .5 .5 .5 .5 .5 .85               WATER    3.0                                                                              3.0                                                                              3.0                                                                              3.0                                                                              3.0                                                                              3.0                                                                              3.0                                                                              3.0                                                                              3.0                                                                              3.0                                                                              3.0                                                                              3.0                                                                              3  3  3  3  4  3                 Al/LV:1/1*                                                                             0.7                                                                              0.7                                                                              0.7                                                                              0.7                                                                              -- -- -- -- 0.6                                                                              0.6                                                                              0.6                                                                              0.6                                                                              -- -- .6 -- .3 --                Al/LV:1/1.5                                                                            -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- .75               Al/LV:1/4                                                                              -- -- -- -- .95                                                                              .95                                                                              .95                                                                              .95                                                                              -- -- -- -- -- -- -- -- -- --                Al/LV:1/1.75                                                                           -- -- -- -- -- -- -- -- -- -- -- -- .65                                                                              .65                                                                              -- .65                                                                              -- --                Al/LV:10 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- .65                                                                              --                ISO INDEX                                                                              90 100                                                                              110                                                                              120                                                                              90 100                                                                              110                                                                              120                                                                              90 100                                                                              110                                                                              120                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100               RESULTS:                                                                      Density (kg/m.sup.3)                                                                   49 44 43 46 42 44 42 42 45 42 41 43 42.3                                                                             43.1                                                                             41.3                                                                             46.4                                                                             36.8                                                                             43.7              Tensile (kPa)                                                                          136                                                                              131                                                                              141                                                                              186                                                                              97 145                                                                              154                                                                              197                                                                              118                                                                              137                                                                              170                                                                              200                                                                              155                                                                              154                                                                              155                                                                              143                                                                              173                                                                              146               Elongation (%)                                                                         170                                                                              134                                                                              134                                                                              114                                                                              157                                                                              153                                                                              136                                                                              145                                                                              159                                                                              148                                                                              144                                                                              137                                                                              153                                                                              144                                                                              160                                                                              156                                                                              134                                                                              156               Tear Strength                                                                          189                                                                              215                                                                              228                                                                              236                                                                              184                                                                              201                                                                              227                                                                              315                                                                              263                                                                              271                                                                              368                                                                              438                                                                              245                                                                              259                                                                              264                                                                              259                                                                              315                                                                              245               (N/m)                                                                         COMPRESSION                                                                   SET (%)*.sup.1                                                                (based on original                                                            deflection)                                                                   2A 50    71.8                                                                             22.1                                                                             22.2                                                                             21.1                                                                             11.9                                                                             10.8                                                                             11.2                                                                             13.9                                                                             20 14.8                                                                             13 21.4                                                                             16.4                                                                             21 16.4                                                                             16.8                                                                             28.4                                                                             19                2A 75    92.7                                                                             93.5                                                                             89 77.1                                                                             56.6                                                                             8.8                                                                              10.4                                                                             12.8                                                                             64 23.5                                                                             11.8                                                                             12.0                                                                             14.4                                                                             25 12.8                                                                             18.2                                                                             20 25.4              2C 50    48.5                                                                             28.3                                                                             25.3                                                                             18.5                                                                             17.5                                                                             13.1                                                                             12.8                                                                             15.7                                                                             18 16.8                                                                             15.4                                                                             15.8                                                                             15.4                                                                             21.4                                                                             19.6                                                                             17.7                                                                             25.2                                                                             16.8              2C 75    87.4                                                                             85.8                                                                             69.7                                                                             17.2                                                                             12.8                                                                             11.3                                                                             11.2                                                                             14.2                                                                             16 14.4                                                                             15.0                                                                             14.2                                                                             16.5                                                                             20.2                                                                             14.1                                                                             13.3                                                                             23.4                                                                             14.9              __________________________________________________________________________     *Al refers to Niax Al, a tertiary amine catalyst available from Union         Carbide; LV refers to Dabco 33LV, a tertiary amine catalyst available fro     Air Products; the numbers (e.g. 1/1, 1/1.5, etc.) refer to the weight         ratio of Al to LV.                                                            *.sup.1 2A is the original foam, while 2C is the foam humid aged to the       Chrysler specification. 50 and 75 are the % deflections for the test.    

Examples 1 through 4 are comparative examples. All the other exampleshad excellent processing characteristics. As far as the compression setdata, in general values of less than 30% are desirable, with the lowerthe % the better the value.

Although the invention has been described in detail in the foregoing forthe purpose of illustration, it is to be understood that such detail issolely for that purpose and that variations can be made therein by thoseskilled in the art without departing from the spirit and scope of theinvention except as it may be limited by the claims.

What is claimed is:
 1. A flexible foam prepared by reacting:(A) frommore than 0 to up to 3 parts by weight per 100 parts by weight ofcomponents (B) and (C) of an amine of the formula:

    H.sub.2 N--R--NH.sub.2

where R is a C₃ to C₁₀ straight or branched alkylene group, or a C₄ toC₁₅ alicyclic group, (B) from 0 to 30% by weight of a polyoxyalkylenepolyamine having a molecular weight of from about 400 to about 5000 andcontaining from 2 to 3 primary amino groups, and (C) from 70 to 100% byweight of one or more polyether polyhydroxyl compounds having hydroxylfunctionalities of from 2 to 3 and molecular weights of from about 1000to about 10,000, the percents by weight of components B) and C)totalling 100%; and (D) a polymethylene poly phenyl isocyanate)containing from about 40 to about 85% by weight of methylenebis(phenylisocyanate) and/or a prepolymer of such isocyanate, said prepolymerhaving an isocyanate content of from about 15 to about 30% by weight, inthe presence of (E) a blowing agent, at an isocyanate index of from 60to
 140. 2. The foam of claim 1, wherein R is a C₃ to C₁₀ branched chainalkylene group.
 3. The foam of claim 2, wherein component (A) is1,5-diamino-2-methylpentane.
 4. The foam of claim 1, wherein component(A) is present in an amount of from 0.05 to 2.5 parts by weight.
 5. Thefoam of claim 4 wherein component (A) is present in an amount of from0.25 to 1.5 parts by weight.
 6. The foam of claim 4 wherein component(B) is present in an amount of from 1 to 20% by weight.
 7. The foam ofclaim 6 wherein component (B) is present in an amount of from 2.5 to 15%by weight.
 8. The foam of claim 1, wherein said index is from 90 to 120.